The evaluation of extracorporeal shock wave therapy on collagenase induced superficial digital flexor tendonitis.

The research article is about a study on the effects of Extracorporeal Shock Wave Therapy (ESWT) on horses with collagenase induced superficial digital flexor tendonitis, concluding that ESWT did not alter the ultrasonographic appearance of the tendons but increased neovascularization.

Objective of the Study

The study sought to evaluate the clinical, ultrasonographic, and histological effects of Extracorporeal Shock Wave Therapy (ESWT) on horses afflicted with collagenase induced superficial digital flexor tendonitis. Such horses were compared with untreated controls.

Methodology

• The research was conducted as a blind study using six mature, healthy horses. The horses served as their controls by inducing bilateral forelimb Superficial Digital Flexor Tendon (SDFT) lesions. One forelimb was treated with ESWT, and the other was left untreated, providing a basis for comparison.
• Three shock wave treatments were administered at three-week intervals to the treated forelimb, while the untreated forelimb was left alone.
• Ultrasonograms were used weekly to measure the percentage of the lesion at the maximum injury zone (MIZ), the grey scale of the SDFT at the MIZ, the percentage of disruption of longitudinal fibres at the MIZ, and the external width of the SDFT throughout the study.
• The presence and nature of swelling over the SDFT, the heat, the response to palpation, and the lameness were evaluated four times during the study.
• At the conclusion of the study, all tendons in the horses were examined histologically to observe the impact of the ESWT on a cellular level.

Findings

• The study observed that the lesion size, grey scale, and longitudinal fibre disruption at MIZ and the sum of each variable changed significantly over time. However, there was no difference noticed between the ESWT treated group and the untreated controls.
• The histopathological examination revealed increased neovascularization (the natural formation of new blood vessels) in the ESWT treated tendons. This suggests that while ESWT may not alter the ultrasonographic appearance of the tendons, it may enhance the healing process by promoting blood flow to the area.

Conclusion

While Extracorporeal Shock Wave Therapy (ESWT) did not alter the ultrasonographic appearance of the tendons in this study, the therapy was found to increase neovascularization. This may suggest that ESWT could help in improving the healing process in horses diagnosed with collagenase induced superficial digital flexor tendonitis. Further research could be beneficial in order to explore this potential benefit in more depth.